Polycarbonate resin is a representative thermoplastic material that has a heat deflection temperature of about 135° C. or higher and can exhibit superior mechanical properties including impact resistance, and excellent self-extinguishing properties, dimensional stability, heat resistance and transparency. Thus, polycarbonate resins are widely used in various applications, such as exterior materials of electronic and electric products, automobile components, and the like.
Thus, when the polycarbonate resin is used as exterior materials of electronic and electric products, or automobile components, flame retardancy to the polycarbonate resin has been required long before for safety in case of fire. For applying the polycarbonate resin to the exterior materials of home electronics, the polycarbonate resin should basically maintain transparency. Further, in order not to damage the polycarbonate resin by heat generated from the electronic components, it should have excellent heat resistance at the same time.
Recently, in order to exhibit a beauty in an appearance of products, it is often to paint the appearance. In this case, after diluting the paint in various organic solvent, the surface of the resin molding article is coated with the diluted paint, and then is dried. In such a process, the organic solvents used as the dilute are permeated into the polycarbonate, so they act as a cause to decrease transparency and mechanical rigidity. Therefore, in order to apply the polycarbonate to the products which can easily occur the contact with various organic solvents in living environment, the resistance to these organic solvent is required.
However, a lot of developments for concurrently improving the flame retardancy and chemical resistance of such a polycarbonate resin have not reported. Most of them have presented several methods for improving flame retardancy or chemical resistance alone.
The known method for concurrently improving chemical resistance and flame retardancy of the polycarbonate is a way to give flame retardancy through blending a resin having chemical resistance with a flame retardant. However, such a method is hard to have sufficient chemical resistance, but impact strength is rapidly deteriorated due to the flame retardant added so as to give flame retardancy. In order to compensate this, impact modifiers are used, but they result in greatly decreasing excellent transparency of the polycarbonate. Moreover, a method of improving flame retardancy or chemical resistance alone brings about a result that does not satisfy a physical property that is another important requirement.
Further, copolymerizing with functional monomer to give flame retardancy satisfied flame retardancy, but there is a drawback which could not satisfy chemical resistance that is the other important requirement.
In case of copolymerizing or blending with other resin to improve chemical resistance, chemical resistance of polycarbonate may be improved, but its transparency is greatly decreased. Thereby, it is impossible to fundamentally improve flame retardancy.